As farm sizes have increased over the years, agricultural implements have necessarily increased in size as well. Wider implements have been generally preferred as being more efficient for covering the increased areas, as opposed to using a plurality of smaller implements. Modern farms also typically include land that is scattered over a considerable area, requiring that these wide implements be put into a narrower transport position for travel from one field to the next on public roads. In order to do so safely while allowing other traffic to pass, and in order move under overhead utility lines, with such wide implements the width and height of implements when in this transport position is limited.
Seeding and cultivating implements typically comprise a frame mounted on wheels, where the frame comprises a plurality of parallel tool bars spaced from the front to the rear of the frame and extending laterally across the width of the implement. Tool assemblies such as cultivator shanks or furrow openers are spaced laterally along each tool bar, with ground engaging tools extending down from the frame to engage the soil. The frame typically comprises a number of separate sections. For example one common type of wide implement has five separate sections comprising a center section, an inner wing pivotally attached to each side of the center section, and an outer wing pivotally attached to outer ends of the inner wings. The pivot axes are substantially horizontal and parallel to the operating travel direction so that the wings and center section can flex with respect to each other to follow ground contours.
A transport configuration for such an implement can be achieved in a number of different ways. U.S. Pat. No. 6,220,366 to Noonan et al. and U.S. Pat. No. 6,089,329 to Smith disclose a five section implement where the wings extend upward in transport. The outer wings are folded over to lie substantially flat above the inner wings, and then the inner wings are raised to an upright orientation such that the outer wings extend downward from the ends of the inner wings and between the inner wings. U.S. Pat. No. 6,092,609 to Jeffrey et al. illustrates an alternate configuration for folding a five section implement for transport where the outer wings are folded substantially vertical to the ends of the inner wings, and the inner wings are raised to a substantially vertical orientation with the outer wings oriented substantially horizontally and aligned end-to end.
The above implements provide 5 separate independent sections when working in the field. Each inner wing can pivot up and down with respect to the center section, and each outer wing can pivot up and down with respect to each inner wing. Such flexibility improves the ability of the implement to flex and follow ground contours to better maintain an even depth for the ground engaging tools typically mounted on the implement.
Alternate implement configurations are known where the implement is folded horizontally rearward or forward such that the wing sections trail behind or ahead of the center section. For example U.S. Pat. No. 5,829,370 to Bender discloses a implement with only two wings which fold rearward. The Bender implement is a planter that has all tools mounted on a single lateral tool bar such that the two wings can come quite closely together.
Most typical cultivation and air seeding implements however have two or more lateral tool bars, with a correspondingly increased distance from the front to the rear of the frame. To accommodate such more typical tool bar implements, U.S. Pat. No. 7,861,795 to Dillon, for example, discloses an implement with a center section and a wing pivotally attached to each end of the center section. To achieve the transport position, the front edges of the wings move upward so that the wings are oriented vertically, and then each wing folds rearward to a trailing position. Similarly U.S. Pat. No. 6,374,923 to the present inventor Friggstad and U.S. Pat. No. 4,821,809 to Summach also disclose implements with wings that pivot upward and then fold to a trailing rearward position for transport.
It is further also known to fold the wings forward, as illustrated for example in U.S. Pat. No. 6,076,613 to Frasier.
Folding the wings upward for transport is convenient for implements such as air seeders, where a separate cart to carry agricultural products is often towed behind the implement. The upward wing orientation however becomes problematic as implement width increases because the height of the implement in the transport position can become excessive. Using the rear folding configuration reduces the height of the implement in transport, and allows for increased implement widths, however has its own problems. For example with rear folding air seeders it is difficult to arrange for towing the product cart behind.